The purpose of the study is to determine how much a persons kidney function recovers after receiving a simultaneous liver kidney transplant. The investigators will be contacting patients with kidney dysfunction with estimated GFR between 25 and 40 (not on dialysis treatment) who are listed to receive a simultaneous liver kidney (SLK) transplant to look at this function recovery. The investigators hope to develop a criteria based on GFR measurement, kidney function calculations from native kidneys vs transplanted kidney and compare the contributions, and correlate with estimated GFR on basic metabolic panel (BMP: a blood test) to predict higher chances of recovery of native kidney function.